If a company develops a new drug and proves its worth in large-scale clinical trials, physicians typically want to examine the evidence for themselves. If the sponsor claims that a new product saves lives, prescribers and patients need to feel comfortable that the claims are valid. Understandably, organizations that are interested in public health are reluctant to endorse most new drugs, partially because of fears that they will be accused of being influenced by industry money. As a result, it generally takes years for a truly life-saving drug to be supported and adopted by the clinical community.
Given this history of caution, the launch of the new Apple Watch Series 4 a week ago raised many an eyebrow.
In case you did not know, the Apple Watch Series 4 includes an FDA-approved heart monitor functionthat is capable of monitoring the electrocardiogram of the person who wears it.
Everyone expected that Apple would make every effort to tout the merits of this new device. Unsurprisingly, news outlets promulgated the Apple announcement with great excitement.
And Dr. Ivor Benjamin, the president of the American Heart Association, spoke favorably about its impact in person at a heavily promoted media event. He referred to the heart app as “game-changing.” Wow!
The American Heart Association never does this. Typically, even when the evidence supporting a new drug or device is overwhelming, the AHA remains silent. The AHA receives considerable funds from the pharmaceutical and device industry, and naturally, it does not want the public to think that its statements are influenced by these financial involvements.
So what was different this time?
Perhaps, the Apple Watch Series 4 actually does save lives. That would justify all of the hype.
However, according to Health News Review, the data supporting the use of the device was based on only 588 people, about half of whom had permanent or persistent atrial fibrillation. Reportedly, the device accurately identified the patient’s underlying rhythm more than 98% of the time. However, the performance of the notification function of the app (which sends an alert to the wearer) was not so stellar.
Is this data summary accurate? I do not know. Typically, the evidence that supports a new drug or device is published in the peer-reviewed medical literature. But as far as I know, the evidence supporting the device has not been subject to peer-review by any journal.
However, even if the data are accurate, it is important to understand that the device has not been approved by the FDA for any defined use. Typically, the FDA approves drugs and devices based on data from studies performed in populations who will use them. The people who will use the Apple Watch represent the general population. But the utility of the Apple Watch has not been evaluated in the general population.
In people who are likely to use the heart monitor function, the prevalence of atrial fibrillation is very low and the rhythm is likely to present as brief and highly infrequent bursts rather than a chronic arrhythmia. The rate of false positives and false negatives is highly dependent on the prevalence of the disorder in the population being evaluated. And accurately detecting a long-standing arrhythmia is not the same as accurately detecting “bursts.”
If the prevalence of atrial fibrillation in those wearing the Watch is less than 1% and if the accuracy of the device varies with the duration of the arrhythmia bursts, the number of false positive alerts is likely to be very high compared with the number of true positive alerts. Dr. Venk Murthy of the University of Michigan has made this very important point very eloquently in the Health News Review article.
So how accurate or useful is the Apple Watch in detecting short infrequent bursts of asymptomatic atrial fibrillation in patients with no known heart disease in whom the prevalence of the arrhythmia is extremely low? We simply do not know.
What does this mean? Two things.
First, the device is likely to alert many truly healthy people, causing enormous and unnecessary anxiety. Most will be motivated to see medical attention, potentially putting horrific pressures on our healthcare system. Even a low false positive error rate is problematic in a low-prevalence population, leading to meaningful squandering of healthcare resources.
Second, the device might detect atrial fibrillation in a few people who did not previously know that they had the arrhythmia. But what benefits does this knowledge provide? What does the presence of these asymptomatic bursts mean? Do they have clinical importance? Should they be treated? No one knows.
Even if the Apple Watch were perfect in its detection of atrial fibrillation in the general population, it is not clear how this information might be helpful. As Health News Review reported, screening of the general population for atrial fibrillation is not recommended. And anticoagulation (or interventions to treat the rhythm disturbance) in the very few patients with newly detected bursts of atrial fibrillation carries risks without known benefits.
As expected, there have been anecdotal reports of a handful of people who became aware of a cardiac diagnosis because they used the Apple Watch. But these stories do not describe “life-saving” events. And they are certainly not being balanced by untold reports of false alarms and unnecessary physician visits and treatments.
Dr. Benjamin may be right. The Apple Watch may be a game-changer — but not in a good way. If the device causes anxiety, yields minimal benefits, and subjects people to unnecessary risks, its utilization will place unwelcome burden on our healthcare system and cause harm to our patients.
Yet, apparently, Apple COO Jeff Williams has dubbed the Watch the “ultimate guardian for your health.” Really?
I do not know if Apple was quoted correctly or in the appropriate context. But Dr. Venk Murthy has responded very admirably: “We’d never accept such broad statements from a pharmaceutical ad, and we shouldn’t accept it from marketing for a device.”
Dr. Murthy is absolutely right. I strongly disagree with the statement attributed to Mr. Williams, and I am really uncomfortable with the public position taken by Dr. Benjamin.
In the current political climate, we relish the opportunity of being skeptical of drugs. It is acceptable (and quite fashionable) to launch missiles at drug manufacturers. All too often, we are right to do so.
Isn’t it time that we held devices to the same standards of truth and evidence?
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